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Spina Bifida
Hydrocephalus
Scotland
Hydrocephalus
Hydrocephalus | www.sbhscotland.org.uk
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What is hydrocephalus?
The brain and spinal cord are surrounded by a clear fluid called cerebrospinal fluid (CSF). This
fluid is produced and stored in cavities (ventricles) in the brain. Each day the brain produces
about a pint of CSF which protects and nourishes the brain, supplies important chemicals
and nutrients and carries away waste from the brain cells. Any excess fluid drains away and
is absorbed by the body.
Hydrocephalus is a condition where the CSF is unable to drain away through the drainage
pathways and fluid accumulates. The ventricles then enlarge to accommodate the
extra fluid which causes pressure on different parts of the brain and compression of the
surrounding tissue. There are two types of hydrocephalus - “Communicating” which
occurs when the flow of CSF is blocked after it exits from the ventricles. It’s known as
communicating because the CSF can still flow between the ventricles which remain open.
“Non-communicating” is also known as obstructive hydrocephalus and occurs when the
flow of CSF is blocked along one or more of the narrow pathways connecting the ventricles.
What causes hydrocephalus?
Congenital hydrocephalus
This is where hydrocephalus is present at birth and it is important to know that this does not
mean that it is hereditary. Often the exact cause is not known and may not be detected on
ante natal scans.
Premature births
The brain of a baby born prematurely is more vulnerable than one at full term as it is still
developing. The area that lies just beneath the lining of the brain is particularly important
as it has a plentiful blood supply. Its blood vessels are very fragile and can easily burst if
the baby has an extreme change in blood pressure or in the amount of fluid in the system.
If these occur, the baby is at risk of developing a haemorrhage from rupture of the fragile
vessels. This can lead to a clot forming which in some cases is big enough to break through
the wall of the ventricle and block the flow of CSF. This blockage can be temporary or
permanent and even if a blood clot does not develop, the blood cells from the haemorrhage
can cause blockage.
Spina bifida
Around 80% of babies born with spina bifida have hydrocephalus due to a malformation of
the brain structure called the Arnold Chiari Malformation.
This develops before birth and prevents proper drainage of the CSF.
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Hydrocephalus | www.sbhscotland.org.uk
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Meningitis
This is an infection of the membranes covering the brain and the inflammation and “debris”
from this infection block the drainage pathways resulting in hydrocephalus. Meningitis can
occur at any age but is most common in children.
Tumours
Tumours can be benign or malignant and can cause compression and swelling of
surrounding tissues resulting in poor drainage of CSF, which may result in hydrocephalus.
Genetic causes
In some rare circumstances, hydrocephalus can be inherited and if there is a history of
hydrocephalus in the family it is advisable to discuss this with a Geneticist to determine the
risk of it recurring.
Dandy Walker Syndrome
This is a congenital brain malformation involving an area at the back of the brain which
controls movement (cerebellum) and the fluid filled spaces surrounding it. Common
features of this syndrome are:
• An enlargement of the fourth cavity (ventricle) in the brain which allows fluid to
flow freely between the upper and lower areas of the brain and spinal cord.
• A partial or complete absence of the area of the brain responsible for coordination
of voluntary muscle movements.
• Fluid-filled cysts near the internal base of the skull which can cause pressure on
the surrounding tissues.
How is hydrocephalus treated?
Some forms of hydrocephalus require no specific treatment. Other forms are temporary
and do not require treatment on a long-term basis. However the most common form of
treatment is by the insertion of a shunt or valve into the brain (diagram on the next page)
which is carried out under a general anaesthetic. This is a small device consisting of a
one-way valve inserted in the brain. This is then attached to a thin silicone tube (catheter)
which is placed just under the skin and ends in the abdominal cavity. This system diverts the
accumulated CSF around the blockage and allows it to drain via the end of the catheter into
the abdominal cavity where it is absorbed into the bloodstream. It is important to note that
this does not “cure” hydrocephalus but prevents the condition becoming worse and any
symptoms caused by the raised pressure usually improve.
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Hydrocephalus | www.sbhscotland.org.uk
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Ventriculoperitoneal
Shunt Placement
Endoscopic Third Ventriculostomy
A procedure called Endoscopic Third Ventriculostomy (ETV) may avoid the need for a shunt.
This is carried out under a general anaesthetic and involves a small perforation made in the
floor of the third ventricle using a small instrument called an endoscope, allowing the CSF to
escape and therefore avoiding the need for a shunt. However not all types of hydrocephalus
can be treated by this method and should be discussed with your Neurosurgeon.
Shunt Alert Cards
If you do have a shunt operation, Spina Bifida Hydrocephalus Scotland can provide you
with a free medical alert card to keep with you at all times. This contains useful
information for both you, your doctor and any medical staff who may need to
care for you. Call SBH Scotland on 03455 211 300 to request your card.
If you have questions or would like further information, please call the
SBH Scotland Helpline on 03455 211 300 or email [email protected]
For general enquiries call 03455 211 811 or visit www.sbhscotland.org.uk
This fact sheet is for informational purposes only. It is not intended to replace or be relied on as medical or professional advice.
Contact us if you require this publication in another format or language.
Spina Bifida Hydrocephalus Scotland is a trading name of the Scottish Spina Bifida Association.
Registered Scottish Charity No. SC013328. Registered office: The Dan Young Building, 6 Craighalbert Way, Dullatur, Glasgow, G68 0LS.
A company limited by guarantee. Registered in Scotland Number 213050.
Updated August 2016 by SBH Scotland’s Medical Advisory Group.
Hydrocephalus | www.sbhscotland.org.uk
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